It's well-known that some popular libraries make use of a few of these internal APIs, such as sun.misc.Unsafe, to invoke methods that would be difficult, if not impossible, to implement outside of the JDK.

... and they will leave it alone in Java 9.

If it does not have a supported replacement in JDK 8 then we will not encapsulate it in JDK 9, so that it remains accessible to outside code

Several prominent Java figures have voiced their approval of the plan. Richard Warburton termed it a 'pragmatic compromise':